Locating and Loading the Mapping File

All mappings are kept in the MTA mapping file. (This is the file specified with the IMTA_MAPPING_FILE option in the MTA tailor
file; by default, this is msg_svr_base/config/mappings.) The contents of the mapping file is incorporated
into the compiled configuration.

The mapping file should be world readable. Failure to allow world-read
access leads to erratic behavior.